<!DOCTYPE html>


<html lang="zh-CN">


<head>
  <meta charset="utf-8" />
    
  <meta name="description" content="迎着朝阳的博客" />
  
  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1" />
  <title>
    设计模式之适配器模式 |  迎着朝阳
  </title>
  <meta name="generator" content="hexo-theme-ayer">
  
  <link rel="shortcut icon" href="https://dxysun.com/static/yan.png" />
  
  
<link rel="stylesheet" href="/dist/main.css">

  
<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/Shen-Yu/cdn/css/remixicon.min.css">

  
<link rel="stylesheet" href="/css/custom.css">

  
  
<script src="https://cdn.jsdelivr.net/npm/pace-js@1.0.2/pace.min.js"></script>

  
  

  
<script>
var _hmt = _hmt || [];
(function() {
	var hm = document.createElement("script");
	hm.src = "https://hm.baidu.com/hm.js?aa994a8d65700b8835787dd39d079d7e";
	var s = document.getElementsByTagName("script")[0]; 
	s.parentNode.insertBefore(hm, s);
})();
</script>


</head>

</html>

<body>
  <div id="app">
    
      
    <main class="content on">
      <section class="outer">
  <article
  id="post-designPatternForAdapter"
  class="article article-type-post"
  itemscope
  itemprop="blogPost"
  data-scroll-reveal
>
  <div class="article-inner">
    
    <header class="article-header">
       
<h1 class="article-title sea-center" style="border-left:0" itemprop="name">
  设计模式之适配器模式
</h1>
 

    </header>
     
    <div class="article-meta">
      <a href="/2021/04/20/designPatternForAdapter/" class="article-date">
  <time datetime="2021-04-20T14:53:31.000Z" itemprop="datePublished">2021-04-20</time>
</a> 
  <div class="article-category">
    <a class="article-category-link" href="/categories/%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F/">设计模式</a>
  </div>
  
<div class="word_count">
    <span class="post-time">
        <span class="post-meta-item-icon">
            <i class="ri-quill-pen-line"></i>
            <span class="post-meta-item-text"> 字数统计:</span>
            <span class="post-count">1.9k</span>
        </span>
    </span>

    <span class="post-time">
        &nbsp; | &nbsp;
        <span class="post-meta-item-icon">
            <i class="ri-book-open-line"></i>
            <span class="post-meta-item-text"> 阅读时长≈</span>
            <span class="post-count">7 分钟</span>
        </span>
    </span>
</div>
 
    </div>
      
    <div class="tocbot"></div>




  
    <div class="article-entry" itemprop="articleBody">
       
  <p>适配器模式</p>
<a id="more"></a>

<h2 id="适配器模式"><a href="#适配器模式" class="headerlink" title="适配器模式"></a>适配器模式</h2><p>适配器模式（Adapter Pattern）又叫做变压器模式，它的功能是将一个类的接口变成客户端所期望的另一种接口，从而使原本因接口不匹配而导致无法在一起工作的两个类能够一起工作，属于结构型设计模式。</p>
<p>也就是说，当前系统存在两种接口A和B，客户只支持访问A接口，但是当前系统没有A接口对象，但是有B接口对象，但客户无法识别B接口，因此需要通过一个适配器C，将B接口内容转换成A接口，从而使得客户能够从A接口获取得到B接口内容。</p>
<p>在软件开发中，基本上任何问题都可以通过增加一个中间层进行解决。适配器模式其实就是一个中间层。综上，适配器模式其实起着转化/委托的作用，将一种接口转化为另一种符合需求的接口。</p>
<h3 id="适配器模式的应用场景"><a href="#适配器模式的应用场景" class="headerlink" title="适配器模式的应用场景"></a>适配器模式的应用场景</h3><p>提供一个转换器（适配器），将当前系统存在的一个对象转化为客户端能够访问的接口对象。</p>
<p>适配器适用于以下几种业务场景：</p>
<p>1、已经存在的类，它的方法和需求不匹配（方法结果相同或相似）的情况。</p>
<p>2、适配器模式不是软件设计阶段考虑的设计模式，是随着软件维护，由于不同产品、不同厂家造成功能类似而接口不相同情况下的解决方案。有点亡羊补牢的感觉。</p>
<p>生活中也非常的应用场景，例如电源插转换头、手机充电转换头、显示器转接头。</p>
<p>适配器模式一般包含三种角色：</p>
<p>目标角色（Target）：也就是我们期望的接口；</p>
<p>源角色（Adaptee）：存在于系统中，内容满足客户需求（需转换），但接口不匹配的接口实例；</p>
<p>适配器（Adapter）：将源角色（Adaptee）转化为目标角色（Target）的类实例；</p>
<p>适配器模式各角色之间的关系如下：</p>
<p>假设当前系统中，客户端需要访问的是Target接口，但Target接口没有一个实例符合需求，而Adaptee实例符合需求；但是客户端无法直接使用Adaptee（接口不兼容）；因此，我们需要一个适配器（Adapter）来进行中转，让Adaptee能转化为Target接口形式；</p>
<p>适配器模式有3种形式：类适配器、对象适配器、接口适配器。</p>
<h3 id="类适配器"><a href="#类适配器" class="headerlink" title="类适配器"></a>类适配器</h3><p>类适配器的原理就是通过继承来实现适配器功能。具体做法：让Adapter实现Target接口，并且继承Adaptee，这样Adapter就具备Target和Adaptee的特性，就可以将两者进行转化。</p>
<p>下面来看UML类图：</p>
<p><img src="https://tu.dxysun.com/image-20210420231952405-20210420231956.png" alt="image-20210420231952405"></p>
<p>源角色（Adaptee）</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">Adaptee</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">    <span class="function"><span class="keyword">public</span> String <span class="title">specificRequest</span><span class="params">(String str)</span></span></span><br><span class="line"><span class="function">    </span>&#123;</span><br><span class="line">        <span class="keyword">return</span> str + <span class="string">" from Adaptee"</span>;</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>目标角色（Target）</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">interface</span> <span class="title">Target</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">    <span class="function">String <span class="title">request</span><span class="params">(String str)</span></span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>适配器（Adapter）</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">Adapter</span> <span class="keyword">extends</span> <span class="title">Adaptee</span> <span class="keyword">implements</span> <span class="title">Target</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">	<span class="meta">@Override</span></span><br><span class="line">	<span class="function"><span class="keyword">public</span> String <span class="title">request</span><span class="params">(String str)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		String res = <span class="keyword">super</span>.specificRequest(str);</span><br><span class="line">		<span class="keyword">return</span> res + <span class="string">" from Adapter"</span>;</span><br><span class="line">	&#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>测试代码</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">Main</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">	<span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		Adapter adapter = <span class="keyword">new</span> Adapter();</span><br><span class="line">		String res = adapter.request(<span class="string">"request"</span>);</span><br><span class="line">		System.out.println(res);  <span class="comment">// 输出:request from Adaptee from Adapter</span></span><br><span class="line">	&#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>



<h3 id="对象适配器"><a href="#对象适配器" class="headerlink" title="对象适配器"></a>对象适配器</h3><p>对象适配器的原理就是通过组合来实现适配器功能。具体做法：让Adapter实现Target接口，然后内部持有Adaptee实例，然后再Target接口规定的方法内转换Adaptee。</p>
<p><img src="https://tu.dxysun.com/image-20210420232802757-20210420232804.png" alt="image-20210420232802757"></p>
<p>适配器（Adapter）</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">Adapter</span> <span class="keyword">implements</span> <span class="title">Target</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">	<span class="keyword">private</span> Adaptee adaptee;</span><br><span class="line"></span><br><span class="line">	<span class="function"><span class="keyword">public</span> <span class="title">Adapter</span><span class="params">(Adaptee adaptee)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		<span class="keyword">this</span>.adaptee = adaptee;</span><br><span class="line">	&#125;</span><br><span class="line"></span><br><span class="line">	<span class="meta">@Override</span></span><br><span class="line">	<span class="function"><span class="keyword">public</span> String <span class="title">request</span><span class="params">(String str)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		String res = adaptee.specificRequest(str);</span><br><span class="line">		<span class="keyword">return</span> res + <span class="string">" from Adapter"</span>;</span><br><span class="line">	&#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>测试代码</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">Main</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">	<span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		Adaptee adaptee = <span class="keyword">new</span> Adaptee();</span><br><span class="line">		Adapter adapter = <span class="keyword">new</span> Adapter(adaptee);</span><br><span class="line">		String res = adapter.request(<span class="string">"request"</span>);</span><br><span class="line">		System.out.println(res);  <span class="comment">// 输出:request from Adaptee from Adapter</span></span><br><span class="line">	&#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>



<h3 id="接口适配器"><a href="#接口适配器" class="headerlink" title="接口适配器"></a>接口适配器</h3><p>接口适配器的关注点与类适配器和对象适配器的关注点不太一样，类适配器和对象适配器着重于将系统存在的一个角色（Adaptee）转化成目标接口（Target）所需内容，而接口适配器的使用场景是解决接口方法过多，如果直接实现接口，那么类会多出许多空实现的方法，类显得很臃肿，此时，使用接口适配器就能让我们只实现我们需要的接口方法，目标更清晰。</p>
<p><img src="https://tu.dxysun.com/image-20210420233903984-20210420233905.png" alt="image-20210420233903984"></p>
<p>目标角色（Target）</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">interface</span> <span class="title">Target</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">    <span class="function">String <span class="title">request1</span><span class="params">(String str)</span></span>;</span><br><span class="line">    <span class="function">String <span class="title">request2</span><span class="params">(String str)</span></span>;</span><br><span class="line">    <span class="function">String <span class="title">request3</span><span class="params">(String str)</span></span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>适配器（Adapter）</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">Adapter</span> <span class="keyword">implements</span> <span class="title">Target</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">	<span class="keyword">private</span> Adaptee adaptee;</span><br><span class="line"></span><br><span class="line">	<span class="function"><span class="keyword">public</span> <span class="title">Adapter</span><span class="params">(Adaptee adaptee)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		<span class="keyword">this</span>.adaptee = adaptee;</span><br><span class="line">	&#125;</span><br><span class="line"></span><br><span class="line">	<span class="meta">@Override</span></span><br><span class="line">	<span class="function"><span class="keyword">public</span> String <span class="title">request1</span><span class="params">(String str)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		String res = adaptee.specificRequest(str);</span><br><span class="line">		<span class="keyword">return</span> res + <span class="string">" from Adapter"</span>;</span><br><span class="line">	&#125;</span><br><span class="line"></span><br><span class="line">	<span class="meta">@Override</span></span><br><span class="line">	<span class="function"><span class="keyword">public</span> String <span class="title">request2</span><span class="params">(String str)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		<span class="keyword">return</span> <span class="string">""</span>;</span><br><span class="line">	&#125;</span><br><span class="line"></span><br><span class="line">	<span class="meta">@Override</span></span><br><span class="line">	<span class="function"><span class="keyword">public</span> String <span class="title">request3</span><span class="params">(String str)</span></span></span><br><span class="line"><span class="function">	</span>&#123;</span><br><span class="line">		<span class="keyword">return</span> <span class="string">""</span>;</span><br><span class="line">	&#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>测试代码</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">class</span> <span class="title">Main</span></span></span><br><span class="line"><span class="class"></span>&#123;</span><br><span class="line">    <span class="function"><span class="keyword">public</span> <span class="keyword">static</span> <span class="keyword">void</span> <span class="title">main</span><span class="params">(String[] args)</span></span></span><br><span class="line"><span class="function">    </span>&#123;</span><br><span class="line">        Adaptee adaptee = <span class="keyword">new</span> Adaptee();</span><br><span class="line">        Adapter adapter = <span class="keyword">new</span> Adapter(adaptee);</span><br><span class="line">        String res = adapter.request1(<span class="string">"req1"</span>);</span><br><span class="line">        System.out.println(res);  <span class="comment">// 输出:req1 from Adaptee from Adapter</span></span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>



<h2 id="适配器模式在源码中的体现"><a href="#适配器模式在源码中的体现" class="headerlink" title="适配器模式在源码中的体现"></a>适配器模式在源码中的体现</h2><p>Spring中适配器模式也应用得非常广泛，例如：SpringAOP中的AdvisorAdapter类，它有三个实现类MethodBeforeAdviceAdapter、 AfterReturningAdviceAdapter和ThrowsAdviceAdapter，先来看顶层接口AdvisorAdapter的源代码：</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">public</span> <span class="class"><span class="keyword">interface</span> <span class="title">AdvisorAdapter</span> </span>&#123;</span><br><span class="line"></span><br><span class="line">	<span class="comment">/**</span></span><br><span class="line"><span class="comment">	 * Does this adapter understand this advice object? Is it valid to</span></span><br><span class="line"><span class="comment">	 * invoke the &#123;<span class="doctag">@code</span> getInterceptors&#125; method with an Advisor that</span></span><br><span class="line"><span class="comment">	 * contains this advice as an argument?</span></span><br><span class="line"><span class="comment">	 * <span class="doctag">@param</span> advice an Advice such as a BeforeAdvice</span></span><br><span class="line"><span class="comment">	 * <span class="doctag">@return</span> whether this adapter understands the given advice object</span></span><br><span class="line"><span class="comment">	 * <span class="doctag">@see</span> #getInterceptor(org.springframework.aop.Advisor)</span></span><br><span class="line"><span class="comment">	 * <span class="doctag">@see</span> org.springframework.aop.BeforeAdvice</span></span><br><span class="line"><span class="comment">	 */</span></span><br><span class="line">	<span class="function"><span class="keyword">boolean</span> <span class="title">supportsAdvice</span><span class="params">(Advice advice)</span></span>;</span><br><span class="line"></span><br><span class="line">	<span class="comment">/**</span></span><br><span class="line"><span class="comment">	 * Return an AOP Alliance MethodInterceptor exposing the behavior of</span></span><br><span class="line"><span class="comment">	 * the given advice to an interception-based AOP framework.</span></span><br><span class="line"><span class="comment">	 * &lt;p&gt;Don't worry about any Pointcut contained in the Advisor;</span></span><br><span class="line"><span class="comment">	 * the AOP framework will take care of checking the pointcut.</span></span><br><span class="line"><span class="comment">	 * <span class="doctag">@param</span> advisor the Advisor. The supportsAdvice() method must have</span></span><br><span class="line"><span class="comment">	 * returned true on this object</span></span><br><span class="line"><span class="comment">	 * <span class="doctag">@return</span> an AOP Alliance interceptor for this Advisor. There's</span></span><br><span class="line"><span class="comment">	 * no need to cache instances for efficiency, as the AOP framework</span></span><br><span class="line"><span class="comment">	 * caches advice chains.</span></span><br><span class="line"><span class="comment">	 */</span></span><br><span class="line">	<span class="function">MethodInterceptor <span class="title">getInterceptor</span><span class="params">(Advisor advisor)</span></span>;</span><br><span class="line"></span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>MethodBeforeAdviceAdapter 源码</p>
<figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line"><span class="class"><span class="keyword">class</span> <span class="title">MethodBeforeAdviceAdapter</span> <span class="keyword">implements</span> <span class="title">AdvisorAdapter</span>, <span class="title">Serializable</span> </span>&#123;</span><br><span class="line"></span><br><span class="line">	<span class="meta">@Override</span></span><br><span class="line">	<span class="function"><span class="keyword">public</span> <span class="keyword">boolean</span> <span class="title">supportsAdvice</span><span class="params">(Advice advice)</span> </span>&#123;</span><br><span class="line">		<span class="keyword">return</span> (advice <span class="keyword">instanceof</span> MethodBeforeAdvice);</span><br><span class="line">	&#125;</span><br><span class="line"></span><br><span class="line">	<span class="meta">@Override</span></span><br><span class="line">	<span class="function"><span class="keyword">public</span> MethodInterceptor <span class="title">getInterceptor</span><span class="params">(Advisor advisor)</span> </span>&#123;</span><br><span class="line">		MethodBeforeAdvice advice = (MethodBeforeAdvice) advisor.getAdvice();</span><br><span class="line">		<span class="keyword">return</span> <span class="keyword">new</span> MethodBeforeAdviceInterceptor(advice);</span><br><span class="line">	&#125;</span><br><span class="line"></span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

<p>Spring会根据不同的AOP配置来确定使用对应的Advice，跟策略模式不同的是一个方法可以同时拥有多个Advice。</p>
<p>SpringMVC中的HandlerAdapter类也是适配器模式，类图如下</p>
<p><img src="https://tu.dxysun.com/image-20210420235541169-20210420235543.png" alt="image-20210420235541169"></p>
<h2 id="适配器模式和装饰器模式对比"><a href="#适配器模式和装饰器模式对比" class="headerlink" title="适配器模式和装饰器模式对比"></a>适配器模式和装饰器模式对比</h2><p>装饰器和适配器模式都是包装模式（Wrapper Pattern），装饰器也是一种特殊的代理模式。</p>
<table>
<thead>
<tr>
<th></th>
<th>装饰器模式</th>
<th>适配器模式</th>
</tr>
</thead>
<tbody><tr>
<td>形式</td>
<td>是一种非常特别的适配器模式</td>
<td>没有层级关系，装饰器模式有层级关系</td>
</tr>
<tr>
<td>定义</td>
<td>装饰器和被装饰器都实现同个接口，主要目的是为了扩展之后依旧保留OOP关系</td>
<td>适配器和被适配者没有必然的联系，采用继承或代理的形式进行包装</td>
</tr>
<tr>
<td>关系</td>
<td>满足is-a的关系</td>
<td>满足has-a的关系</td>
</tr>
<tr>
<td>功能</td>
<td>注重覆盖、扩展</td>
<td>注重兼容、转换</td>
</tr>
<tr>
<td>设计</td>
<td>前置考虑</td>
<td>后置考虑</td>
</tr>
</tbody></table>
<h2 id="适配器模式的优缺点"><a href="#适配器模式的优缺点" class="headerlink" title="适配器模式的优缺点"></a>适配器模式的优缺点</h2><p>优点：</p>
<p>1、能提高类的透明性和复用，现有的类复用但不需要改变。</p>
<p>2、目标类和适配器类解耦，提高程序的扩展性。</p>
<p>3、在很多业务场景中符合开闭原则。</p>
<p>缺点：</p>
<p>1、适配器编写过程需要全面考虑，可能会增加系统的复杂性。</p>
<p>2、增加代码阅读难度，降低代码可读性，过多使用适配器会使系统代码变得凌乱。</p>
 
      <!-- reward -->
      
      <div id="reword-out">
        <div id="reward-btn">
          打赏
        </div>
      </div>
      
    </div>
    

    <!-- copyright -->
    
    <footer class="article-footer">
       
<div class="share-btn">
      <span class="share-sns share-outer">
        <i class="ri-share-forward-line"></i>
        分享
      </span>
      <div class="share-wrap">
        <i class="arrow"></i>
        <div class="share-icons">
          
          <a class="weibo share-sns" href="javascript:;" data-type="weibo">
            <i class="ri-weibo-fill"></i>
          </a>
          <a class="weixin share-sns wxFab" href="javascript:;" data-type="weixin">
            <i class="ri-wechat-fill"></i>
          </a>
          <a class="qq share-sns" href="javascript:;" data-type="qq">
            <i class="ri-qq-fill"></i>
          </a>
          <a class="douban share-sns" href="javascript:;" data-type="douban">
            <i class="ri-douban-line"></i>
          </a>
          <!-- <a class="qzone share-sns" href="javascript:;" data-type="qzone">
            <i class="icon icon-qzone"></i>
          </a> -->
          
          <a class="facebook share-sns" href="javascript:;" data-type="facebook">
            <i class="ri-facebook-circle-fill"></i>
          </a>
          <a class="twitter share-sns" href="javascript:;" data-type="twitter">
            <i class="ri-twitter-fill"></i>
          </a>
          <a class="google share-sns" href="javascript:;" data-type="google">
            <i class="ri-google-fill"></i>
          </a>
        </div>
      </div>
</div>

<div class="wx-share-modal">
    <a class="modal-close" href="javascript:;"><i class="ri-close-circle-line"></i></a>
    <p>扫一扫，分享到微信</p>
    <div class="wx-qrcode">
      <img src="//api.qrserver.com/v1/create-qr-code/?size=150x150&data=https://dxysun.com/2021/04/20/designPatternForAdapter/" alt="微信分享二维码">
    </div>
</div>

<div id="share-mask"></div>  
  <ul class="article-tag-list" itemprop="keywords"><li class="article-tag-list-item"><a class="article-tag-list-link" href="/tags/%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F/" rel="tag">设计模式</a></li></ul>

    </footer>
  </div>

   
  <nav class="article-nav">
    
      <a href="/2021/04/21/designPatternForBridge/" class="article-nav-link">
        <strong class="article-nav-caption">上一篇</strong>
        <div class="article-nav-title">
          
            设计模式之桥接模式
          
        </div>
      </a>
    
    
      <a href="/2021/04/18/designPatternForComposite/" class="article-nav-link">
        <strong class="article-nav-caption">下一篇</strong>
        <div class="article-nav-title">设计模式之组合模式</div>
      </a>
    
  </nav>

  
   
  
</article>

</section>
      <footer class="footer">
  <div class="outer">
    <ul>
      <li>
        Copyrights &copy;
        2015-2024
        <i class="ri-heart-fill heart_icon"></i> dxysun
      </li>
    </ul>
    <ul>
      <li>
        
        
        
        由 <a href="https://hexo.io" target="_blank">Hexo</a> 强力驱动
        <span class="division">|</span>
        主题 - <a href="https://github.com/Shen-Yu/hexo-theme-ayer" target="_blank">Ayer</a>
        
      </li>
    </ul>
    <ul>
      <li>
        
        
        <span>
  <span><i class="ri-user-3-fill"></i>访问人数:<span id="busuanzi_value_site_uv"></span></s>
  <span class="division">|</span>
  <span><i class="ri-eye-fill"></i>浏览次数:<span id="busuanzi_value_page_pv"></span></span>
</span>
        
      </li>
    </ul>
    <ul>
      
        <li>
          <a href="https://beian.miit.gov.cn" target="_black" rel="nofollow">豫ICP备17012675号-1</a>
        </li>
        
    </ul>
    <ul>
      
    </ul>
    <ul>
      <li>
        <!-- cnzz统计 -->
        
      </li>
    </ul>
  </div>
</footer>
      <div class="float_btns">
        <div class="totop" id="totop">
  <i class="ri-arrow-up-line"></i>
</div>

<div class="todark" id="todark">
  <i class="ri-moon-line"></i>
</div>

      </div>
    </main>
    <aside class="sidebar on">
      <button class="navbar-toggle"></button>
<nav class="navbar">
  
  <div class="logo">
    <a href="/"><img src="https://dxysun.com/static/logo.png" alt="迎着朝阳"></a>
  </div>
  
  <ul class="nav nav-main">
    
    <li class="nav-item">
      <a class="nav-item-link" href="/">主页</a>
    </li>
    
    <li class="nav-item">
      <a class="nav-item-link" href="/archives">归档</a>
    </li>
    
    <li class="nav-item">
      <a class="nav-item-link" href="/categories">分类</a>
    </li>
    
    <li class="nav-item">
      <a class="nav-item-link" href="/tags">标签</a>
    </li>
    
    <li class="nav-item">
      <a class="nav-item-link" href="/photos">相册</a>
    </li>
    
    <li class="nav-item">
      <a class="nav-item-link" href="/friends">友链</a>
    </li>
    
    <li class="nav-item">
      <a class="nav-item-link" href="/about">关于我</a>
    </li>
    
  </ul>
</nav>
<nav class="navbar navbar-bottom">
  <ul class="nav">
    <li class="nav-item">
      
      <a class="nav-item-link nav-item-search"  title="搜索">
        <i class="ri-search-line"></i>
      </a>
      
      
      <a class="nav-item-link" target="_blank" href="/atom.xml" title="RSS Feed">
        <i class="ri-rss-line"></i>
      </a>
      
    </li>
  </ul>
</nav>
<div class="search-form-wrap">
  <div class="local-search local-search-plugin">
  <input type="search" id="local-search-input" class="local-search-input" placeholder="Search...">
  <div id="local-search-result" class="local-search-result"></div>
</div>
</div>
    </aside>
    <script>
      if (window.matchMedia("(max-width: 768px)").matches) {
        document.querySelector('.content').classList.remove('on');
        document.querySelector('.sidebar').classList.remove('on');
      }
    </script>
    <div id="mask"></div>

<!-- #reward -->
<div id="reward">
  <span class="close"><i class="ri-close-line"></i></span>
  <p class="reward-p"><i class="ri-cup-line"></i>请我喝杯咖啡吧~</p>
  <div class="reward-box">
    
    <div class="reward-item">
      <img class="reward-img" src="https://tu.dxysun.com/alipay-20201219151322.jpg">
      <span class="reward-type">支付宝</span>
    </div>
    
    
    <div class="reward-item">
      <img class="reward-img" src="https://tu.dxysun.com/weixin-20201219151346.png">
      <span class="reward-type">微信</span>
    </div>
    
  </div>
</div>
    
<script src="/js/jquery-2.0.3.min.js"></script>


<script src="/js/lazyload.min.js"></script>

<!-- Tocbot -->


<script src="/js/tocbot.min.js"></script>

<script>
  tocbot.init({
    tocSelector: '.tocbot',
    contentSelector: '.article-entry',
    headingSelector: 'h1, h2, h3, h4, h5, h6',
    hasInnerContainers: true,
    scrollSmooth: true,
    scrollContainer: 'main',
    positionFixedSelector: '.tocbot',
    positionFixedClass: 'is-position-fixed',
    fixedSidebarOffset: 'auto'
  });
</script>

<script src="https://cdn.jsdelivr.net/npm/jquery-modal@0.9.2/jquery.modal.min.js"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/jquery-modal@0.9.2/jquery.modal.min.css">
<script src="https://cdn.jsdelivr.net/npm/justifiedGallery@3.7.0/dist/js/jquery.justifiedGallery.min.js"></script>

<script src="/dist/main.js"></script>

<!-- ImageViewer -->

<!-- Root element of PhotoSwipe. Must have class pswp. -->
<div class="pswp" tabindex="-1" role="dialog" aria-hidden="true">

    <!-- Background of PhotoSwipe. 
         It's a separate element as animating opacity is faster than rgba(). -->
    <div class="pswp__bg"></div>

    <!-- Slides wrapper with overflow:hidden. -->
    <div class="pswp__scroll-wrap">

        <!-- Container that holds slides. 
            PhotoSwipe keeps only 3 of them in the DOM to save memory.
            Don't modify these 3 pswp__item elements, data is added later on. -->
        <div class="pswp__container">
            <div class="pswp__item"></div>
            <div class="pswp__item"></div>
            <div class="pswp__item"></div>
        </div>

        <!-- Default (PhotoSwipeUI_Default) interface on top of sliding area. Can be changed. -->
        <div class="pswp__ui pswp__ui--hidden">

            <div class="pswp__top-bar">

                <!--  Controls are self-explanatory. Order can be changed. -->

                <div class="pswp__counter"></div>

                <button class="pswp__button pswp__button--close" title="Close (Esc)"></button>

                <button class="pswp__button pswp__button--share" style="display:none" title="Share"></button>

                <button class="pswp__button pswp__button--fs" title="Toggle fullscreen"></button>

                <button class="pswp__button pswp__button--zoom" title="Zoom in/out"></button>

                <!-- Preloader demo http://codepen.io/dimsemenov/pen/yyBWoR -->
                <!-- element will get class pswp__preloader--active when preloader is running -->
                <div class="pswp__preloader">
                    <div class="pswp__preloader__icn">
                        <div class="pswp__preloader__cut">
                            <div class="pswp__preloader__donut"></div>
                        </div>
                    </div>
                </div>
            </div>

            <div class="pswp__share-modal pswp__share-modal--hidden pswp__single-tap">
                <div class="pswp__share-tooltip"></div>
            </div>

            <button class="pswp__button pswp__button--arrow--left" title="Previous (arrow left)">
            </button>

            <button class="pswp__button pswp__button--arrow--right" title="Next (arrow right)">
            </button>

            <div class="pswp__caption">
                <div class="pswp__caption__center"></div>
            </div>

        </div>

    </div>

</div>

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/photoswipe@4.1.3/dist/photoswipe.min.css">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/photoswipe@4.1.3/dist/default-skin/default-skin.min.css">
<script src="https://cdn.jsdelivr.net/npm/photoswipe@4.1.3/dist/photoswipe.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/photoswipe@4.1.3/dist/photoswipe-ui-default.min.js"></script>

<script>
    function viewer_init() {
        let pswpElement = document.querySelectorAll('.pswp')[0];
        let $imgArr = document.querySelectorAll(('.article-entry img:not(.reward-img)'))

        $imgArr.forEach(($em, i) => {
            $em.onclick = () => {
                // slider展开状态
                // todo: 这样不好，后面改成状态
                if (document.querySelector('.left-col.show')) return
                let items = []
                $imgArr.forEach(($em2, i2) => {
                    let img = $em2.getAttribute('data-idx', i2)
                    let src = $em2.getAttribute('data-target') || $em2.getAttribute('src')
                    let title = $em2.getAttribute('alt')
                    // 获得原图尺寸
                    const image = new Image()
                    image.src = src
                    items.push({
                        src: src,
                        w: image.width || $em2.width,
                        h: image.height || $em2.height,
                        title: title
                    })
                })
                var gallery = new PhotoSwipe(pswpElement, PhotoSwipeUI_Default, items, {
                    index: parseInt(i)
                });
                gallery.init()
            }
        })
    }
    viewer_init()
</script>

<!-- MathJax -->

<script type="text/x-mathjax-config">
  MathJax.Hub.Config({
      tex2jax: {
          inlineMath: [ ['$','$'], ["\\(","\\)"]  ],
          processEscapes: true,
          skipTags: ['script', 'noscript', 'style', 'textarea', 'pre', 'code']
      }
  });

  MathJax.Hub.Queue(function() {
      var all = MathJax.Hub.getAllJax(), i;
      for(i=0; i < all.length; i += 1) {
          all[i].SourceElement().parentNode.className += ' has-jax';
      }
  });
</script>

<script src="https://cdn.jsdelivr.net/npm/mathjax@2.7.6/unpacked/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
<script>
  var ayerConfig = {
    mathjax: true
  }
</script>

<!-- Katex -->

<!-- busuanzi  -->


<script src="/js/busuanzi-2.3.pure.min.js"></script>


<!-- ClickLove -->

<!-- ClickBoom1 -->

<!-- ClickBoom2 -->

<!-- CodeCopy -->


<link rel="stylesheet" href="/css/clipboard.css">

<script src="https://cdn.jsdelivr.net/npm/clipboard@2/dist/clipboard.min.js"></script>
<script>
  function wait(callback, seconds) {
    var timelag = null;
    timelag = window.setTimeout(callback, seconds);
  }
  !function (e, t, a) {
    var initCopyCode = function(){
      var copyHtml = '';
      copyHtml += '<button class="btn-copy" data-clipboard-snippet="">';
      copyHtml += '<i class="ri-file-copy-2-line"></i><span>COPY</span>';
      copyHtml += '</button>';
      $(".highlight .code pre").before(copyHtml);
      $(".article pre code").before(copyHtml);
      var clipboard = new ClipboardJS('.btn-copy', {
        target: function(trigger) {
          return trigger.nextElementSibling;
        }
      });
      clipboard.on('success', function(e) {
        let $btn = $(e.trigger);
        $btn.addClass('copied');
        let $icon = $($btn.find('i'));
        $icon.removeClass('ri-file-copy-2-line');
        $icon.addClass('ri-checkbox-circle-line');
        let $span = $($btn.find('span'));
        $span[0].innerText = 'COPIED';
        
        wait(function () { // 等待两秒钟后恢复
          $icon.removeClass('ri-checkbox-circle-line');
          $icon.addClass('ri-file-copy-2-line');
          $span[0].innerText = 'COPY';
        }, 2000);
      });
      clipboard.on('error', function(e) {
        e.clearSelection();
        let $btn = $(e.trigger);
        $btn.addClass('copy-failed');
        let $icon = $($btn.find('i'));
        $icon.removeClass('ri-file-copy-2-line');
        $icon.addClass('ri-time-line');
        let $span = $($btn.find('span'));
        $span[0].innerText = 'COPY FAILED';
        
        wait(function () { // 等待两秒钟后恢复
          $icon.removeClass('ri-time-line');
          $icon.addClass('ri-file-copy-2-line');
          $span[0].innerText = 'COPY';
        }, 2000);
      });
    }
    initCopyCode();
  }(window, document);
</script>


<!-- CanvasBackground -->


<script src="/js/dz.js"></script>



    
  </div>
</body>

</html>